“Good morning sir,” said a green gingham dress (the uniform of the Wiltons waitress).

“Good morning,” I bade back. “Good morning, my Lord,” said a brace of pinstriped trousers as I sat.

“Good morn…” I began, swivelling around, before recalling that I have no ermine robe. The echt peer was at the next table.

Something felt odd. I glanced at the mobile (strictly banned by the menu). It was 1.06pm.

“I can’t tell you how thrilled I am to be back here after so many years,” said Robin, an old family friend and my senior accountant, as I joined this intergenerational lunch with him, his son Alistair (junior accountant) and my own pater. “It hasn’t changed a bit.”

It has, in fact, this grand and stately High Tory temple: so subtly, though, that it’s easily missed. This back room, faintly scented with paraffin from the roast-of-the-day trolley, has been repainted various warm, autumnal pastels, its walls newly bedecked by colourful culinary paintings. It’s less crusty than it was and jollier than the oakily sombre main bit where the grandees eat at banquettes. But it’s been careful evolution. Revolution wouldn’t suit Wiltons.

But the prices. Oh, those prices.

“I’ll have the wild smoked salmon,” said Robin, beaming at a menu eschewing any hint of voguishness to concentrate on the luxuriously plain dishes (oysters, fish, roasts and game) Wiltons has done so well for so long.

“That would be the wild smoked salmon?” I confirmed.

“It would.”

“Well,” I said, stifling a retch on noting the price, “that’s tremendous. We’ll all ignore the set menu, then? By the way, that note you sent me about essential cutbacks in personal expenditure… perhaps that can wait.”

I liberated him from the petrifying wine list. “Allow me,” I said, alighting on a decent sauvignon blanc at a fairly indecent £48. “It would break my heart if anything deflected you from your salmon.”

That smoked fish, as at £28 it perhaps should have been, was superb. “Not at all oily, and a wonderfully delicate taste,” Robin said. “Unimprovable.”

Alistair liked his marinated salmon, and my father his immaculately fresh dressed crab.

It was over my economy drive beef consommé that the first generational split opened up, us younguns finding it wildly oversalted. However, the tribal elders, raised in wartime and the austerity years when any flavour at all was a godsend, did not. My father, whose mother would use the contents of two Siberian salt mines to season a salmon rissole, dismissed the criticism with a dunno-they’re-born shrug.

The ensuing debate about hot shrapnel and Anderson shelters ended with the arrival of five main courses. The extra one, as thoughtfully suggested by Robin, was the generous portion of perfectly rare and melty roast sirloin off the trolley that caused an etiquette panic. Do you still tip the carver? We decided that, at these prices, you do not.

The accountants self-sacrificially confined themselves to Dover soles — a whole fish off the bone for père. light and greaseless goujons for fils — and raved about the quality of that piscine princeling and the accuracy of its cooking.

My father loved his ruby red slices of Fallow deer venison while, this being Wiltons in the game season, I had the roast grouse with all the trimmings (fried, crushed oatcake known as gravel, bread sauce, rich wine gravy and its own wickedly rich livers on toast).

An old editor of mine always ordered a brace. “Stick ’em in the oven for 10 minutes,” he’d say when a gingham dress inquired, “wipe their bums, and serve.”

Less manly, I had it medium. The pinkish meat was as juicy, musty and intimate as this sovereign of all game birds should be. The second generational dispute erupted over the vegetable. The broccoli, which struck us sons as overboiled, was ideal for the paters. Taste in veg, unlike Wiltons, has changed dramatically down the years.

An elegant lady left with her dog. “I wish to protest in the strongest terms,” I told the manager.

“That lady is permitted to bring her dog,” he replied.

“And why,” I blimpishly harrumphed, “is that?”

“Because she is Mrs Hambro, sir,” he said, “and she is the owner.”

Also gone by 2.30pm were the chief executive of Goldman Sachs, his lordship and everyone else but us. The quality, it seems, likes to lunch early. Being the quantity, we stuck around to share a sensationally good trifle.

“A fabulous restaurant,” Robin said, “and precisely as it should be. Now, I want to see you soon for a chat about your spending.”

I checked the bill, grabbing at the corner of the table for support. “I really must, mustn’t I?” I murmured. “I absolutely must control the spending.”

“Good morning, sir, and see you again soon,” said a pair of pinstripes as I left. I was bemused.

Then it hit me. This splendid, bring-the-mortgage-deeds restaurant has evidently purchased its own bespoke time zone. At Wiltons, whatever Robert Browning thought, it is always glad confident morning, and ever more shall be so.